This invention generally relates to a graphical user interface for displaying data on a display of a data processing system in an object-oriented software program. More particularly, it relates to a single control for changing a plurality of parameters each of which range in value along a respective scale.
To provide accessibility and ease of use to the functions of a modern day data processing system, it has become commonplace to construct a Graphical User Interface (GUI) to control the system. To maximize the amount of information while maintaining the legibility of that information presented by computer display, certain display controls have been employed.
Traditionally, linearly or logarithmically scaled variables such as volume or balance are controlled by the use of a slider or a knob in a graphical user interface. Such variables can be changed within a given range, e.g., from zero to a predetermined maximum value by manipulating the appearance of the slider or knob in the GUI. As the two functions are independent of each other, there is generally one knob for volume control and another knob for balance control. To change a parameter associated with a slider or a knob the user will bring a pointer, typically controlled by a mouse, to a particular volume portion of the slider or a knob, and manipulate the slider or knob appearance.
While this type of graphical user interface is adequate, as the number of applications which share the available presentations space in the GUI proliferate in number, screen space becomes a premium. Generally, the display space allocated to each application's window will shrink in size. When an application uses a number of controls for each of the variables, not all of them can be displayed at the same time. Therefore, it would be desirable to have a control which could manipulate a plurality of independent variables.
Further, while variable pairs such as volume and balance, bass and treble, contrast and brightness are independent of each other, conceptually they are related. It would be desirable to have a control which can change such pairs of conceptually related parameters simultaneously.
This invention teaches such a control.